Crane mechanism

Abstract

A crane structure for hoisting, holding and/or towing heavy loads is provided. The crane structure includes a frame, for example a wrecker truck chassis, a boom support assembly, and a pair of booms each having a first member pivotally mounted to the boom support assembly so that the first boom and the second boom are pivotal in parallel vertical planes. Each of the first boom and the second boom also has a fluid operable second member slidably received by the first member. A control system is in operative communication with the first boom, the second boom and a winch assembly to independently activate each second member to extend from and retract to its corresponding first member, to pivotally position each boom with respect to the frame, and to activate the winch assembly to retract and extend cables about free ends of the respective second members.

What is claimed: 
     
       1. A crane truck for hoisting, holding and/or towing heavy loads, said crane truck comprising: a mobile chassis;   a boom support assembly mounted to said chassis;   a first boom and a second boom, each said boom being extendable rearward from said chassis and having a first section pivotally mounted to said boom support assembly so that said first boom and said second boom are pivotal in parallel vertical planes, each of said first boom and said second boom also having a fluid operable second section slidably received by said first section;   a winch assembly including a base assembly and a pair of cables, each cable of said pair of cables extending from said base assembly about free ends of respective said second sections, each said cable having a securing mechanism at a free end thereof opposite said base assembly for securing a load; and   a control system in operative communication with said first boom, said second boom and said winch assembly, said control system configured to independently activate each said second section to extend from and retract to its corresponding said first section, to pivotally position each of said first boom and said second boom with respect to said chassis, and to activate said winch assembly to retract and extend said cables about said free ends of said respective second sections, to thereby manipulate a single load with both said booms.   
     
     
       2. The crane truck as in claim 1, wherein said first boom and said second boom are independently pivotable in their respective said parallel vertical planes. 
     
     
       3. The crane truck as in claim 1, wherein said first section of said first boom and said first section of said second boom are attached in parallel to each other on opposite sides of a substantially vertical plane so that said first boom and said second boom are maintained parallel to each other. 
     
     
       4. The crane truck as in claim 1, wherein said first section of said first boom is attached parallel to and above said first section of said second boom so that said first boom and said second boom are maintained parallel to each other. 
     
     
       5. A wrecker truck for hoisting, holding and/or towing heavy loads, said hoisting structure comprising: a wheeled chassis;   a boom support assembly mounted to said chassis;   a first boom and a second boom, each said boom extending rearward from said boom support assembly with respect to said chassis and having a first section pivotally mounted to said boom support assembly so that said first boom and said second boom are maintained in and pivotal in parallel vertical planes, each of said first boom and said second boom also having a fluid operable second section slidably received by said first member;   a winch assembly including a base assembly and a pair of cables, each cable of said pair of cables extending from said base assembly about free ends of respective said second sections, each said cable having a securing mechanism at a free end thereof opposite said base assembly for securing a load; and   a control system in operative communication with said first boom, said second boom and said winch assembly, said control system configured to independently activate each said second section to extend from and retract to its corresponding said first section, to pivotally position each of said first boom and said second boom with respect to said chassis, and to activate said winch assembly to retract and extend said cables about said free ends of said respective second sections, to thereby manipulate a single load with both said booms.   
     
     
       6. The wrecker truck as in claim 5, wherein said first boom and said second boom are configured to pivot separately in their respective said parallel vertical planes. 
     
     
       7. The wrecker truck as in claim 5, wherein said first section of said first boom and said first section of said second boom are attached in parallel to each other on opposite sides of a substantially vertical plane to maintain said first boom and said second boom parallel to each other. 
     
     
       8. The wrecker truck as in claim 5, wherein said first section of said first boom is attached parallel to and above said first section of said second boom to maintain said first boom and said second boom parallel to each other. 
     
     
       9. The wrecker truck as in claim 5, wherein each said second section has one or more pulleys positioned at its outer end for operative cooperation with one or more said cables. 
     
     
       10. The wrecker truck as in claim 9, wherein each of said first boom and said second boom includes a fluid-operable, cylinder/piston extension ram arranged within said boom, said extension ram having one end connected to the interior of said first section and another end connected to the interior of said second section whereby activation of said ram produces outward extension of said second section and, therefore, said one or more pulleys relative to the boom support mechanism. 
     
     
       11. The wrecker truck as in claim 5, wherein said base assembly includes a mast structure. 
     
     
       12. The wrecker truck as in claim 5, including at least one fluid-operable, cylinder/piston elevation ram operatively associated with each of said first boom and said second boom, each said elevation ram having an end connected adjacent the outer end of said first section and another end secured to said chassis, wherein each said elevation ram, when activated, is configured to pivot its respective said boom within a range of orientations between minimum and maximum angular positions. 
     
     
       13. A wrecker truck for hoisting, holding and/or towing heavy loads, said hoisting structure comprising: a chassis;   a boom support assembly mounted to said chassis;   a first boom and a second boom each having a first section pivotally mounted to said boom support assembly so that said first boom and said second boom are pivotal in parallel vertical planes, each of said first boom and said second boom also having a fluid operable second section slidably received by said first section;   a winch assembly including a base assembly and a pair of cables, each cable of said pair of cables extending from said base assembly about free ends of respective said second sections, each said cable having a securing mechanism at a free end thereof opposite said base assembly for securing a load; and   a control system in operative communication with said first boom, said second boom and said winch assembly, said control system configured to independently activate each said second section to extend from and retract to its corresponding said first section, to pivotally position each of said first boom and said second boom with respect to said chassis, and to activate said winch assembly to retract and extend said cables about said free ends of said respective second sections,   wherein said first section of said first boom and said first section of said second boom are attached in parallel to each other on opposite sides of a substantially vertical plane by a unitary sleeve including said first section of said first boom and said first section of said second boom to maintain said first boom and said second boom parallel to each other.   
     
     
       14. A wrecker truck for hoisting, holding and/or towing heavy loads, said hoisting structure comprising: a chassis;   a boom support assembly mounted to said chassis;   a first boom and a second boom each having a first section pivotally mounted to said boom support assembly so that said first boom and said second boom are pivotal in parallel vertical planes, each of said first boom and said second boom also having a fluid operable second section slidably received by said first section;   a winch assembly including a base assembly and a pair of cables, each cable of said pair of cables extending from said base assembly about free ends of respective said second sections, each said cable having a securing mechanism at a free end thereof opposite said base assembly for securing a load; and   a control system in operative communication with said first boom, said second boom and said winch assembly, said control system configured to independently activate each said second section to extend from and retract to its corresponding said first section, to pivotally position each of said first boom and said second boom with respect to said chassis, and to activate said winch assembly to retract and extend said cables about said free ends of said respective second sections,   wherein said first section of said first boom is attached parallel to and above said first section of said second boom by a unitary sleeve including said first section of said first boom and said first section of said second boom to maintain said first boom and said second boom parallel to each other.   
     
     
       15. A crane truck for hoisting, holding and/or towing heavy loads, said crane truck comprising: a mobile chassis;   a boom support assembly mounted to said chassis;   a first boom and a second boom having respective first sections pivotally mounted to said boom support assembly by a common mount so that said first boom and said second boom are pivotal in parallel vertical planes, each of said first boom and said second boom also having a fluid operable second section slidably received by said first section;   a winch assembly including a base assembly and a pair of cables, each cable of said pair of cables extending from said base assembly about free ends of respective said second sections, each said cable having a securing mechanism at a free end thereof opposite said base assembly for securing a load; and   a control system in operative communication with said first boom, said second boom and said winch assembly, said control system configured to independently activate each said second section to extend from and retract to its corresponding said first section, to pivotally position each of said first boom and said second boom with respect to said chassis, and to activate said winch assembly to retract and extend said cables about said free ends of said respective second sections, to thereby manipulate a single load with both said booms.   
     
     
       16. The crane truck as in claim 15, wherein said first boom and said second boom are independently pivotable in their respective said parallel vertical planes. 
     
     
       17. The crane truck as in claim 15, wherein said first section of said first boom and said first section of said second boom are attached in parallel to each other on opposite sides of a substantially vertical plane so that said first boom and said second boom are maintained parallel to each other. 
     
     
       18. The crane truck as in claim 15, wherein said first section of said first boom is attached parallel to and above said first section of said second boom so that said first boom and said second boom are maintained parallel to each other. 
     
     
       19. The crane truck as in claim 15, wherein said first boom first section and said second boom first section are commonly mounted to said boom support assembly by a horizontal pin extending through both said first sections. 
     
     
       20. A crane truck for hoisting, holding and/or towing heavy loads, said crane truck comprising: a mobile chassis;   a boom support assembly mounted to said chassis;   a first boom and a second boom having respective first sections pivotally mounted to said boom support assembly so that said first boom and said second boom are pivotal in parallel vertical planes, each of said first boom and said second boom also having a fluid operable second section slidably received by said first section;   a winch assembly including a base assembly and a pair of cables, each cable of said pair of cables extending from said base assembly about free ends of respective said second sections, each said cable having a securing mechanism at a free end thereof opposite said base assembly for securing a load; and   means for independently activating each said second section to extend from and retract to its corresponding said first section, for pivotally positioning each of said first boom and said second boom with respect to said chassis, and for activating said winch assembly to retract and extend said cables about said free ends of said respective second sections, to thereby manipulate a single load with both said booms.   
     
     
       21. The crane truck as in claim 1, wherein said first boom and said second boom are mounted on said boom support assembly so that they are maintained in said parallel vertical planes.